BNR 하수처리시스템에서 효과적 고형물 분리를 위한 DAF 공정의 적용과 처리특성

곽동희,유대환 대한상하수도학회 2010 상하수도학회지 Vol.24 No.3

Many plants have been improved to adapt the target of the biological treatment processes changed from organics to nutrients since the water quality criteria of effluent was reinforced and included T-N and T-P for the municipal wastewater treatment plant. To meet the criteria of T-N and T-P, the conventional biological reactor such as aeration tank in activated sludge system is changed to the BNR (biological nutrient removal) processes, which are typically divided into three units as anaerobic, anoxic and oxic tank. Therefore, the solid separation process should be redesigned to fit the BNR processes in case of the application of the DAF (dissolved air flotation) process as an alternatives because the solid-liquid separation characteristics of microbial flocs produced in the BNR processes are also different from that of activated sludge system as well. The results of this study revealed that the microbial floc of the anaerobic tank was the hardest to be separated among the three steps of the unit tanks for the BNR processes. On the contrary, the oxic tank was best for the removal efficiency of nutrients as well as suspended solid. In addition, the removal efficiency of nutrients was much improved under the chemical coagulation treatment though coagulation was not indispensable with a respect to the solid separation. On the other hand, in spited that the separation time for the microbial floc from the BNR processes were similar to the typical particles like clay flocs, over 2.32×10³ ppm of air volume concentration was required to keep back the break-up of the bubble-floc agglomerates.

정수장 float 를 형성하는 미세기포의 실채와 영향인자

곽동희,김영철,이성우,정팔진 ( Dong Heui Kwak,Youngchul Kim,Sung Woo Lee,Paul Gene Chung ) 한국물환경학회 1998 한국물환경학회지 Vol.14 No.2

General type of processes treating a water for its public use in Korea, are chemically aided sedimentation tanks followed by rapid sand filters. Settled sludge from a coagulation/flocculation and sedimentation process is easily drained into the sludge treatment train from the bottom of tanks but sludge floated along with numerous micro-bubbles on the surface of coagulation/flocculation tanks and head-part of sedimentation tanks, initially built and operated without a skimmer and barrier against moving floats, has caused serious aesthetic and operational problems. In this study, sources of the micro-bubbles combining with floc particles and causing floating sludge, and factors affecting formation of those bubbles were investigated. There are several factors which can produce gas bubbles in the water treatment plant. Pumps and conduits highly pressurized during water intake and transport to the water treatment plant might be one of the possibilities which can produce micro-bubbles due to the pressure differences. The amounts of nitrogen and carbon dioxide gases evolved during prechlorination and coagulation processes were calculated by using actual plant operational data. Changes of interfacial properties of coagulated water were examined as a possibility of enhancing micro-bubbles production. Among these three factors, it was found that changes of surface characteristics had a significant and direct effect on the formation of micro-bubbles at this plant.

빗물의 용도결정을 위한 세균학적 안전성 및 수질 평가

곽동희,독고석,한무영 대한상하수도학회 2003 상하수도학회지 Vol.17 No.5

Recently, there has been an increasing interest to promote the utilization of rainwater. In this paper, concentration of organic compound and heavy metal in rainwater samples was analyzed to examine the hazardous level of rainwater for utilization. And an experiment for separating the opportunistic and pathogenic bacteria was also performed. Unlike the quality of ground water and surface water, only a few couple of bacteria types have found in the rainwater samples. This means that the quality of rainwater is by far safer than other water sources. Many opportunistic colony which inhabits in nature was found in the most of samples while the pathogenic bacteria was not detected. Organic compounds have not found in rainwater. Concentration of heavy metal in it also shows under the regulation of drinking water. Conclusively, on the basis of the analysis results on five samples, rainwater could be used directly for various purpose without additional water treatment process.

작품리뷰 - 프로젝트 80716

곽동희,Gwak, Dong-Hui 대한건축사협회 2001 建築士 Vol.2001 No.8

2002년도 공동 춘계 학술발표회 논문집 : 발표장 ; 수질분석 : 분말활성탄에 의한 VOC의 흡착특성 및 DAF공정에의 적용

곽동희,이재욱,이종원,정홍조,한민우,최승필 한국물환경학회 ( 구 한국수질보전학회 ) 2002 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2002 No.-

DAF공정에서 개체군 수지를 이용한 기포-플록 응집체의 부상효율과 수리학적 부하율의 운전특성 평가

곽동희 대한상하수도학회 2008 상하수도학회지 Vol.22 No.5

Quantification and Classifying of Livestock Load into Point and Non-Point Source Pollution in Large Scale Livestock Complex of Agricultural Area

곽동희,김희준,이병학,황제아,김종국 한국환경기술학회 2022 한국환경기술학회지 Vol.23 No.1

Livestock manure discharged from agricultural areas has different treatment and fertilization processes depending on the type of livestock. Swine manure is generally treated in livestock wastewater treatment plants and then sprayed as liquid fertilizer or discharged into rivers, whereas cattle manure is composted in livestock excreta resource facilities such as biogas plants, and a large amount is applied to the land. However, the source unit of the livestock manure load applied in Korea's total maximum daily load (TMDL) is not divided into point pollution type and non-point pollution type. The species and pollution load of livestock manure generated in Yongji Watershed where swine are the main livestock, and Dukcheon Watershed where cattle are mainly raised were investigated through a series of measurements and calculations. The result of this study showed the pollution load of livestock manure was clearly classified into PS type and NPS type, and in particular, the NPS pollution load was relatively large. As for the results measured in two watersheds of different livestock breeds, swine and cattle, BOD and TP showed high EMC concentrations in cattle breeding areas, whereas TN showed significantly higher values in swine breeding zones. This finding led us to conclude that there are differences in the water quality management criteria to be focused on depending on the type of livestock. In addition, the load of NPS was fluctuated sensitively to the rainfall intensity, and it implied that the rainfall intensity should be considered as one of the influencing factors when a pollution load of livestock manure is applied to the TMDL.

용존이산화탄소부상(DCF) 공정의 입자분리 특성과 부상효율

곽동희,이영동,정흥조,김성진,유영훈,박양균 대한상하수도학회 2011 상하수도학회지 Vol.25 No.4

A series of laboratory experiments carried out to investigate the particle separation efficiency and flotation characteristics using CO2 bubbles. The primary objective of this study was to find out the feasibility of CO2 bubbles as an applicable unit of flotation process in tap-water and wastewater treatment plant. The fundamental measurements were conducted to characterize the CO2 bubble from the physical viewpoint in water including bubble size distribution and rising velocity under various operational conditions. In addition, the removal efficiency of solid was experimented using the lab scale plant applied CO2 bubbles, namely the dissolved carbon dioxide flotation (DCF) process. The DCF process using carbon dioxide bubble, which is an advantage as the decrease and the reuse of Green-House gas, can be a promising technology as an water treatment process. On the other hand, the further research to decrease the bubble size distribution of CO2 is required to enhance the particle separation efficiency. A series of laboratory experiments carried out to investigate the particle separation efficiency and flotation characteristics using CO2 bubbles. The primary objective of this study was to find out the feasibility of CO2 bubbles as an applicable unit of flotation process in tap-water and wastewater treatment plant. The fundamental measurements were conducted to characterize the CO2 bubble from the physical viewpoint in water including bubble size distribution and rising velocity under various operational conditions. In addition, the removal efficiency of solid was experimented using the lab scale plant applied CO2 bubbles, namely the dissolved carbon dioxide flotation (DCF) process. The DCF process using carbon dioxide bubble, which is an advantage as the decrease and the reuse of Green-House gas, can be a promising technology as an water treatment process. On the other hand, the further research to decrease the bubble size distribution of CO2 is required to enhance the particle separation efficiency.

원수중의 천연유기물이 부상분리공정에 미치는 영향

곽동희,정팔진,이성우 全北大學校 附設 都市및環境硏究所 1997 都市 및 環境硏究 Vol.12 No.1

Many water bodies used for water supply may contain solid particles with a lower density. These solids are hardly removed in the sedimentation unit due to the own tendency of floating. In order to treat this type of water, the flotation process in known to be an effective method. A series of laboratory experiments has been performed to investigate the effect of natural organic matter(NOM) in raw water on flotation process. Foam formation potential(FFP) could be increase by NOM in raw water, alum is stimulate the trend of FFP to increase. Results of DAF treatment studies show that flotation efficiency can be increase by AOM, such as ethyl ester, sodium propionate, sodium dodecylbenzenesulfonate. Meanwhile, flotation efficiency can be decrease by AOM, such as glycerol, starch, pentane, peptone, isoamyl alcohol, humic acid etc. Also, the flotation efficiency by AOM corresponds well the tendency of FFP.

2000 년도 공동추계 학술발표회 / 상수처리 (2) : DAF 공정에서의 무기성 입자 제거특성

곽동희,이재욱 대한상하수도학회 2000 공동추계 학술발표회 논문집 Vol.2000 No.-